GB/T 1511-2016 English PDF (GB/T1511-2016)

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GB/T 1511-2016: Manganese ores -- Determination of calcium and magnesium contents -- EDTA titrimetric method
GB/T 1511-2016
Manganese ores -- Determination of calcium and magnesium contents -- EDTA titrimetric method
ICS 73.060.20
D32
National Standards of People's Republic of China
Replacing GB/T 1511-2006
Determination of calcium and magnesium content in manganese ores
EDTA titration
(ISO 6233.1983, Manganeseoresandconcentrates-Determinationofcalcium
Published on.2016-10-13
2017-09-01 Implementation
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
Released by the Standardization Administration of China
Determination of calcium and magnesium content in manganese ores
EDTA titration
WARNING - Persons using this standard should have practical experience in formal laboratory work. This standard does not address all possible safety issues
question. It is the user's responsibility to take appropriate safety and health measures and to ensure compliance with the conditions stipulated by relevant national regulations.
1 Scope
This standard specifies the determination of calcium and magnesium content in manganese ore by EDTA titration.
This standard is applicable to the determination of calcium and magnesium content in manganese ore.
1.50%~6.00%.
2 Normative references
The following documents are essential for the application of this document. For dated references, only the dated version applies to this article
pieces. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 2011 Bulk manganese ore sampling and sample preparation method (GB/T 2011-1987, neqISO 3081.1983)
GB/T 6682 Analysis Laboratory Water Specifications and Test Methods (GB/T 6682-2008, ISO 3696.1987, MOD)
GB/T 8170 Numerical Rounding Rules and Representation and Judgment of Limit Values
GB/T 14949.8 Manganese ore chemical analysis method Determination of wet water content (GB/T 14949.8-1994, eqvISO 310.
1981)
3 Principles
The sample is decomposed with acid, the residue is melted with sodium carbonate, and manganese, iron, aluminum, titanium, copper, nickel, vanadium, chromium and other dry substances are separated with hexamethylenetetramine and copper reagents.
disturbing elements. Divide a part of the test solution into pH≥12 solution, in the presence of calcein indicator, titrate calcium content with EDTA standard solution,
Another part of the solution was taken in the solution of pH=10, and the amount of calcium and magnesium was titrated with EDTA standard titration solution with chrome black T as indicator.
4 Reagents and Materials
In the analysis process, only use approved analytical reagents and water of grade 3 and above in accordance with GB/T 6682.
4.1 Anhydrous sodium carbonate, solid.
4.2 Nitric acid, ρ=1.42g/mL.
4.3 Hydrochloric acid, ρ=1.19g/mL.
4.4 Hydrofluoric acid, ρ=1.15g/mL.
4.5 Sulfuric acid, ρ=1.84g/mL.
4.6 Ammonia, ρ=0.91g/mL.
4.7 Sulfuric acid, 1 1.
4.8 Hydrochloric acid, 1.1.
4.9 Hydrochloric acid, 14.
4.10 Hydrochloric acid, 1 50.
4.11 Potassium hydroxide,.200g/L, stored in a plastic bottle.
4.12 Sodium diethyldithiocarbamate, 100g/L. Abbreviated as copper reagent solution, it is prepared when used.
4.13 Sucrose solution, 40g/L.
4.14 Ammonium sulfate solution, 50g/L.
4.15 Hexamethylenetetramine solution, 100g/L.
4.16 Buffer solution, pH=10.Weigh 35g of ammonium chloride and dissolve it in.200mL of ammonia water (ρ=0.91g/mL), dilute with water to
500mL, mix well.
4.17 Calcium standard solution. Weigh 2.4970g of benchmark calcium carbonate (burned at.200℃ for 2h and cooled to room temperature in a desiccator) in 250mL
In a beaker, heat and dissolve with 50mL hydrochloric acid (1 4), boil to remove carbon dioxide, cool, transfer to a 1000mL volumetric flask, and dilute with water
to the mark, mix well and set aside. 1 mL of this standard solution contains 1.00 mg of calcium.
4.18 Magnesium standard solution. Weigh 1.6583g of standard magnesium oxide (burned at 850℃ for 1h in advance and cooled to room temperature in a desiccator) in
Add 20mL of hydrochloric acid (1.1) to a 250mL beaker, heat to dissolve, cool and transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix well
spare. 1 mL of this standard solution contains 1.00 mg of magnesium.
4.19 Disodium ethylenediaminetetraacetate (EDTA) standard titration solution, c(C10H14N2O8Na2·2H2O)=0.01mol/L
4.19.1 Preparation of Disodium Ethylenediaminetetraacetate (EDTA) Standard Titration Solution
Weigh 4.0g EDTA (C10H14N2O8Na2·2H2O) in a 400mL beaker, add water to dissolve with slight heat. Filter with medium speed filter paper
In a 1000mL volumetric flask, dilute to the mark with water and mix.
4.19.2 Calibration of disodium ethylenediaminetetraacetate (EDTA) standard titration solution
4.19.2.1 Pipette 3 parts of 10.00mL magnesium standard solution (see 4.18), place them in 250mL beakers respectively, add 15mL buffer solution
(see 4.16) add water to dilute about 150mL, add an appropriate amount of chrome black T indicator (see 4.21), and titrate with EDTA standard under constant stirring
The solution (see 4.19) is titrated until the solution changes from wine red to pure blue.
Calculate the titer of EDTA standard titration solution to magnesium according to formula (1).
T1=
c1×V1
V2-V3
(1)
where.
T1---the titer of EDTA standard titration solution to magnesium, the unit is grams per milliliter (g/mL);
c1 --- the magnesium content in the magnesium standard solution, in grams per milliliter (g/mL);
V1---10.00, pipette the volume of magnesium standard solution, the unit is milliliter (mL);
V2---the volume of EDTA standard titration solution consumed during titration, in milliliters (mL);
V3---The volume of EDTA standard titration solution consumed when titrating the blank test solution, the unit is milliliter (mL).
4.19.2.2 Pipette 3 parts of 10.00mL calcium standard solution (see 4.17), put them in 250mL beakers, dilute to about 150mL with water,
Add 5 mL of sucrose solution (see 4.13), add 1 to 2 drops of malachite green solution (see 4.20) dropwise, the solution is blue-green at this time, dissolve in potassium hydroxide
(see 4.11) until the solution is colorless, then add 10 mL in excess, add an appropriate amount of calcein indicator (see 4.22), drop with EDTA standard
Titrate the solution (see 4.19) until the green fluorescence disappears in the solution as the end point.
Calculate the titer of EDTA standard solution to calcium according to formula (2).
T2=
c2×V4
V5-V6
(2)
where.
T2---the titer of EDTA standard titration solution to calcium, the unit is grams per milliliter (g/mL);
c2 --- the content of calcium in the calcium standard solution, in grams per milliliter (g/mL);
V4---10.00, pipette the volume of calcium standard solution, the unit is milliliter (mL);
V5---the volume of EDTA standard titration solution consumed during titration, in milliliters (mL);
V6---The volume of EDTA standard titration solution consumed when titrating the blank test solution, the unit is milliliter (mL).
4.20 Malachite green solution, 10mg/mL.
4.21 For chrome black T indicator, 0.1 g of chrome black T is mixed with sodium chloride 1.100 and ground in a mortar.
4.22 Calcein indicator, calcein. thymolphthalein. sodium chloride = 1.1.100, mix and grind finely.
5 Instruments
The usual laboratory instruments and equipment were used in the analysis.
6 Take samples
According to the provisions of GB/T 2011, the sample size should be no more than 0.080mm.
7 Analysis steps
7.1 Number of analyses
Perform at least two replicate analyses on the same sample.
7.2 Sample size
Weigh 0.50g air-dried sample, accurate to 0.0001g. According to GB/T 14949.8, determine the moisture content at the same time.
7.3 Blank test
A blank test was carried out with the sample.
7.4 Determination
7.4.1 Put the sample (see 7.2) in a 250mL beaker, add 15mL~20mL of hydrochloric acid (see 4.3), heat to dissolve the sample, add
10mL of nitric acid (see 4.2) was heated until no small bubbles were formed, removed, cooled and then added with 10mL of sulfuric acid (see 4.7), and heated at low temperature until just bubbling
Sulfuric acid fumes, remove and cool.
7.4.2 Add 10mL~15mL hydrochloric acid (see 4.3), heat for 3min~5min, dissolve the salts, add 30mL~40mL hot water, add
Boil with heat, cool, filter with fast filter paper containing pulp, wash the residue and filter paper 3~4 times with hydrochloric acid washing solution (see 4.10), then use hot water
Wash 3 to 4 times, keep the filtrate, and steam the filtrate to about 100mL.
7.4.3 Transfer the filter paper with residues into a platinum crucible, dry at low temperature, carbonize, and then ashing at 500℃~600℃, take it out and cool it for a while, use
Wet the residue with 2 to 3 drops of water, add 2 to 3 drops of sulfuric acid (see 4.7) and 5 mL to 7 mL of hydrofluoric acid (see 4.4), heat and evaporate to dryness.
Ignition at 500℃~600℃, add 1g~2g anhydrous sodium carbonate (see 4.1) after cooling, melt at 900℃~1000℃ for 5min, cool down, divide
Add hydrochloric acid dropwise (see 4.8), heat until the frit is separated from the platinum crucible, and combine this solution with the main solution (see 7.4.2).
7.4.4 Boil the mixture (see 7.4.3) to 40mL~50mL, add ammonia water (see 4.6) dropwise and shake until stable ferric hydroxide precipitates.
If it appears, dissolve it with hydrochloric acid (see 4.8) until the precipitate just disappears. When neutralizing the blank test solution, the amount of ammonia water (see 4.6) and hydrochloric acid (see 4.8) used is the same as the test.
The liquid consumption is the same; add 5 mL of ammonium sulfate solution (see 4.14), add 30 mL of hexamethylenetetramine solution (see 4.15), heat in a water bath to dissolve
liquid to 80 ℃ ~ 90 ℃, and keep 15min ~ 20min, cooling; add 80mL copper reagent solution (see 4.12), transfer into.200mL volume
In the bottle, dilute with water to the mark, mix well, filter with double-layer medium-speed filter paper in a dry 500mL conical flask, discard the initial filtrate. if
The solution was cloudy and was filtered again with double-layer filter paper.
7.4.5 Pipette 50.00mL filtrate (see 7.4.4) in two parts into a 250mL conical flask, and one part is used for titration of calcium content. Dilute with water to body
Accumulate about 150mL, add 5mL sucrose solution (see 4.13), add 1 to 2 drops of malachite green solution (see 4.20), the solution is blue-green at this time,
Then use potassium hydroxide solution (see 4.11) to adjust the solution to a colorless, excess 10mL, add an appropriate amount of calcein indicator (see 4.22), use